A safety lock as taught herein comprises first and second members and is configured to lockably mount to an interlock switch. In one or more embodiments, the second member slidably couples to the first member and slides between a disengaged position that allows for mounting and an engaged position that engages a corresponding switch actuator opening in the interlock switch. In at least one embodiment, the second member projects through an opening in the first member into engagement. The first and second members may include corresponding lock openings, allowing the second member to be locked into the engaged position. In at least one embodiment, the first member conforms at least partially to the exterior of the interlock switch, e.g., it spans at least one exterior corner of the interlock switch. The first member may include an engagement finger to engage a corresponding switch actuator opening of the interlock switch.
|
1. A safety lock configured to lockably mount to an interlock switch, the safety lock comprising:
a first member configured to conform at least partially to a profile of the interlock switch; and
a second member lockable to the first member in an engaged position, wherein the second member engages a first switch actuator opening in the interlock switch.
14. A safety lock for lockably mounting to an interlock switch that includes one or more switch actuator openings, the safety lock comprising:
a first member configured to slidably retain a second member;
said second member movable between an engaged position in which the second member engages a first switch actuator opening of the interlock switch, and a disengaged position in which the second member disengages from the first switch actuator opening.
18. A method of safety locking an interlock switch comprising:
engaging at least two faces of the interlock switch with a first member that is angled or otherwise bent to wrap around the at least two faces of the interlock switch;
inserting a second member through an opening in the first member, such that the second member engages a first switch actuator opening disposed in a first one of the at least two faces of the interlock switch; and
locking the second member to the first member in the engaged position.
2. The safety lock of
3. The safety lock of
4. The safety lock of
5. The safety lock of
6. The safety lock of
7. The safety lock of
8. The safety lock of
9. The safety lock of
10. The safety lock of
11. The safety lock of
12. The safety lock of
13. The safety lock of
15. The safety lock of
16. The safety lock of
17. The safety lock of
19. The method of
|
This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application 60/710,227, which was filed on 22 Aug. 2005 and is entitled “Safety Lock for Interlock Switch,” and which is incorporated herein by reference.
1. Field of the Invention
The present invention generally relates to interlock switches, and particularly relates to a safety lock for interlock switches.
2. Background Information
A common type of safety interlock includes a switch and an actuator. In a common configuration, the actuator includes a finger and the switch includes a slotted head configured to receive the actuator finger. In one arrangement, positive engagement of the actuator finger in the head slot turns the switch on, while disengagement of the actuator finger from the head slot turns the switch off. While it is common for the actuator to have a single finger, the switch head may have more than one slot. For example, there may be one or more switch actuator openings (e.g., slots) on adjacent or opposing faces of the head, allowing the switch to be mounted in different orientations.
For machine guarding applications, the actuator may be mounted to a moveable guard (or access panel, door, gate, etc.), with the switch mounted in a corresponding fixed position such that closure of the guard causes the actuator to engage the switch. While this arrangement provides reliable machine lockout on guard opening, it does not necessarily prevent accidental or mistaken operation of the switch while the movable guard is open.
Safety locks eliminate, or at least greatly reduce, the possibility of accidental reengagement of the safety interlock. In a common safety lock configuration, the safety lock includes a tab that inserts into the switch head slot that would otherwise be engaged by the actuator finger. Such safety locks usually include a moveable piece (e.g., sliding or rotating) that locks the tab into the slot. The moveable piece is then locked into position using a padlock, for example.
Some implementations of the above type of safety lock do not engage with the head slot as securely as merited by the safety-critical nature of the application. For example, some safety locks, even when locked into place, can be disengaged from the switch head by twisting, pulling, or other manipulation.
In one or more embodiments taught herein, a safety lock is configured to lockably mount to an interlock switch and comprises a first member configured to conform at least partially to a profile of the interlock switch, and a second member lockable to the first member in an engaged position. In its engaged position, the second member engages a first switch actuator opening in the interlock switch. In at least one such embodiment, the second member of the safety lock is slidably coupled to the first member and configured to slide between a disengaged position and the engaged position. Further, in one or more embodiments, the first and second members include corresponding lock openings that are configured to align with each other when the second member is in its engaged position, thereby allowing the second member to be locked into the engaged position.
Further, in one or more embodiments taught herein, the first member of the safety lock comprises one or more plate sections that are bent or otherwise angled to span at least one exterior corner of the interlock switch. For example, a single elongated plate can be bent such that it includes one or more corners, allowing it to span two or more faces of a rectangular interlock switch head. A terminal one of these plate sections of the first member includes or otherwise integrates an engaging finger to engage a second switch actuator opening in the interlock switch. As the first and second switch actuator openings are disposed in different faces of the interlock switch, the safety lock in such configurations engages at least two faces of the interlock switch when mounted to the interlock switch.
In more detail, at least one configuration of the safety lock corresponds to an interlock switch that includes first and second switch actuator openings disposed in first and second faces, respectively, of the interlock switch. In such configurations, a method of safety locking the interlock switch comprises engaging at least two faces of the interlock switch with the first member of the safety lock, which is angled or otherwise bent to wrap around the at least two faces of the interlock switch, and inserting the second member through an opening in the first member. In doing so, the second member engages the first switch actuator opening disposed in a first one of the at least two faces of the interlock switch. Locking the second member to the first member in the engaged position thereby secures the safety lock to the interlock switch.
For further engagement security, the first member may include or otherwise integrate an engagement finger, wherein engaging the first member with the interlock switch includes inserting the engagement finger into the second one of the switch actuator openings. Mounting the safety lock thus comprises positioning the second member in its disengaged position, engaging the second switch actuator opening of the interlock switch with the engagement finger of the first member and seating or otherwise placing the first member into abutting engagement with the spanned faces of the interlock switch. Once the first member is in place, the second member is slid through a slot, notch, or other opening in the first member, and into engagement with the first switch actuator opening, and locked into place via aligned lock openings in the first and second members.
In terms of sliding engagement of the second member, in at least one embodiment taught herein, a safety lock comprises a first member configured to slidably retain a second member. In such configurations, the second member is movable between an engaged position in which the second member engages a first switch actuator opening of an interlock switch, and a disengaged position in which the second member disengages from the first switch actuator opening. Further, in such configurations, the first member may be configured to wrap around at least one corner of the interlock switch.
For example, in one such embodiment, the first member comprises first, second, and third sections. The first section is disposed at one end of the second section and projects perpendicularly away from the second section, and the third section is disposed at the other end of the second section and projects perpendicularly away from the second section in a direction opposite the first section. The third section may be the terminal or ending section of the first member and may include an engagement finger for engaging a switch actuator opening of the interlock switch. However, in at least one embodiment, the first member includes a fourth section perpendicularly extending from an end of the third section, to thereby span another corner of the interlock switch. In such embodiments, the fourth section may include an engagement finger for engaging a switch actuator opening in the interlock switch.
Of course, the present invention is not limited to the above features and advantages. Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.
Regarding such switch actuator openings 14, other slot orientations (such as vertical or angled) may be used, and other opening types, such as circular openings, may be used. In general, it should be understood that the interlock switch 10 can be varied. For example, it may not have as many switch actuator openings as illustrated. Instead, it may have at least one switch head face without a switch actuator opening 14. Further, it may have switch head faces with more than one switch actuator opening 14.
Generally, in one or more embodiments, the first member 22 comprises one or more plate sections that are bent or otherwise angled to span at least one exterior corner of the interlock switch 10. In at least one such embodiment, the first member 22 comprises a first section on which the second member 24 is slidably retained, a second section perpendicular to the first section that is configured to abut a first face of the interlock switch 10, and a third section perpendicular to the second section and parallel to the first section that is configured to abut a second face of the interlock switch 10. As such, the first member 22 may comprise a first section, a second section perpendicularly extending from an end of the first section, and a third section perpendicularly extending from an end of the second section, such that the first and third sections are in parallel and perpendicularly extend in opposite directions from respective ends of the second section.
With such configurations, the first member may further comprise a fourth section perpendicularly extending from an end of the third section, such that the fourth section is parallel to the second section and spaced apart from the second section as a function of the third section's length. In any case, a terminal one of these sections, e.g., the third section for three-section embodiments and the fourth section for four-section embodiments, may include an engagement finger configured to engage a second one of the switch actuator openings 14 in a second face of the interlock switch 10, wherein the second member 24 engages a first one of the switch actuator openings 14 in a first face of the interlock switch 10. With these first and second switch actuator openings disposed in different faces of the interlock switch 10, the safety lock 20 engages at least two faces of the interlock switch 10 when mounted to the interlock switch 10.
Turning to the particular details illustrated in
Those skilled in the art will appreciate that the fingers of the safety lock 20 (e.g., fingers 26 and 34) generally are designed to engage corresponding switch actuator openings 14 on the interlock switch head 12. Thus, the finger design may be varied to suit different styles of openings 14. For the horizontally slotted openings 14 illustrated in
With these variations in mind, in at least one embodiment, the second member 24 is slidably coupled to first member 22, e.g., the first section 28 of the first member 22 may be configured to slidably retain the second member 24. With this configuration, the second member 24 slides between a first, disengaged position and a second, engaged position. Thus, in one or more embodiments, the first member 22 is configured to slidably retain the second member 24. The second member 24 is movable between an engaged position in which it engages a first one of the switch actuator openings 14 of the interlock switch 10, and a disengaged position in which it disengages from that first one of the switch actuator openings 14.
Notably, the second section 30 of the first member 22 or a junction area of the first and second sections 28 and 30, respectively, of the first member 22 includes a member opening through which the second member at least partially projects when the second member is slid into the engaged position. The opening may be a slot, notch, void, or other such feature as is appropriate for allowing the second member 24 to project at least partially through the first member 22 when the second member 24 is moved into its engaged position.
With such engagement in mind, one sees that to securely mount the safety lock 20 onto the interlock switch 10, one positions the second member 24 in its disengaged position, which, with reference to
Thus, in the illustrated embodiment of the safety lock 20, one sees that the first and second members 22 and 24 of the safety lock 20 are attached together by the connecting hardware 37, allowing them to move in relationship with each other. The illustrated embodiment provides for linear sliding motion of the second member 24 relative to the first member 22. Further, the first and second members 22 and 24 each have an engagement finger for engaging different openings 14 of the switch head 12. Note that safety lock 20 can be configured such that the length (depth) and offset or height of these fingers (26 and 34) is appropriate for the particular dimensions and configuration of the switch 10, and that different safety locks 20 can be made for different sizes of switches and/or for different makes and models of switches.
In terms of proportioning the safety lock 20, the following relationships, as shown in
In any case,
Looking at further details and opportunities for variation,
With this illustrated arrangement, the interior corners 42 and 44 formed by sections 30, 32, and 40 of the first member 22 wrap around the two exterior corners of the switch head 12. Thus, it may not be necessary for the first member 22 to include an engaging finger, because the mechanical interference associated with this wrap-around configuration prevents removal of the safety lock 20 from the switch 10, assuming that the finger 26 of the second member 24 has been moved into engagement with the corresponding switch actuator opening 14 of the switch head 12 and locked into place with the first member 22.
However,
One sees that formation of the finger 34 of the first member 22 and the finger 26 of the second member 24 are part of the machining process. Thus, as shown in
With these and other variations in mind, one or more embodiments of the safety lock 20 as taught herein offer a number of advantages. By way of non-limiting example, these advantages include the fact that the openings 14 can be at any relative position to each other; for pass-through configurations of the first and second members 22 and 24, the safety lock 20 cannot be removed from force applied in angular motion, because of the pass through arrangement and because of the engagement of the finger 34 with the switch actuator opening 14-1 and of the finger 26 with the switch actuator opening 14-2, the same safety lock 20 can be used to lockout similar interlock switches 10 with different dimensions.
With the above range of variations in mind, it should be understood that the present invention is not limited by the foregoing description, nor is it limited by the accompanying drawings. Instead, the present invention is limited only by the following claims, and their legal equivalents.
Puddicombe, II, Richard J, Borjon, Joseph David
Patent | Priority | Assignee | Title |
10453626, | Jun 29 2017 | HONDA MOTOR CO , LTD | Systems and methods including gate lockout units |
7956300, | Sep 05 2005 | IDEC Corporation | Safety holder |
8598477, | Oct 13 2009 | GARVIN INDUSTRIES, INC ; Southwire Company, LLC | Universal switch restraint device |
8748759, | Aug 12 2011 | Panduit Corp | Circuit breaker lockout |
8839649, | Mar 07 2013 | Master Lock Company LLC | Lockout device |
8847086, | Apr 26 2011 | Master Lock Company LLC | Lockout device |
8937259, | Oct 13 2009 | GARVIN INDUSTRIES, INC ; Southwire Company, LLC | Universal electrical circuit breaker locking device |
Patent | Priority | Assignee | Title |
1197020, | |||
3666259, | |||
4200774, | Aug 21 1978 | Key-operated electrical switch assembly | |
4733029, | May 23 1985 | Mitsubishi Denki Kabushiki Kaisha | Operating handle locking device for circuit interrupter |
4864834, | Mar 08 1989 | WIREMOLD COMPANY, THE | Safety lock |
4897515, | Dec 09 1988 | Siemens Energy & Automation, Inc. | Securing device for the switch handle of a circuit breaker |
5020342, | Oct 03 1989 | 529900 Ontario Ltd. | Safety lock |
5167135, | Sep 13 1991 | East Carolina University | Safety lockout adapter and coupling member used therefor |
5365757, | Jun 21 1993 | NORTH SAFETY PRODUCTS L L C | Safety lock |
5732575, | Oct 10 1996 | Caterpillar Inc. | Hasp type latch |
5881582, | Aug 27 1997 | Panduit Corp.; Panduit Corp | Multi-purpose lockout |
5909019, | Dec 30 1997 | Eaton Corporation | Front mounting plate with integral locking tab |
6268574, | Apr 29 1999 | Electrical and pneumatic lock-out device | |
6310305, | Jan 14 1999 | Idec Izumi Corporation | Safety switch |
6388213, | Mar 17 2000 | General Electric Company | Locking device for molded case circuit breakers |
6396008, | Feb 08 2001 | EATON INTELLIGENT POWER LIMITED | Handle lock device and electrical switching apparatus employing the same |
6459052, | May 12 2000 | Omron Corporation | Key unit and switch body and door switch using the same |
6617532, | Feb 21 2002 | BRADY WORLDWIDE, INC | Circuit breaker lockout device |
6727441, | Sep 04 2002 | Brady Worldwide, Inc. | Switch lever lock out assembly |
6791040, | Sep 15 2003 | EATON INTELLIGENT POWER LIMITED | Locking assembly for an electrical switching apparatus |
7223927, | Jul 02 2005 | ICS TRIPLEX EMEA LIMITED; Rockwell Automation Limited | Lockable switch mechanism |
DE8120397, | |||
GB2377081, | |||
WO9956295, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Aug 21 2006 | Scientific Technologies Incorporated | (assignment on the face of the patent) | / | |||
Aug 21 2006 | PUDDICOMBE, II, RICHARD J | Scientific Technologies Incorporated | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 018151 | /0407 | |
Aug 21 2006 | BORJON, JOSEPH DAVID | Scientific Technologies Incorporated | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 018151 | /0407 | |
Oct 09 2006 | Scientific Technologies Incorporated | OMRON SCIENTIFIC TECHNOLOGIES, INC | CHANGE OF NAME SEE DOCUMENT FOR DETAILS | 027500 | /0440 |
Date | Maintenance Fee Events |
Jan 30 2012 | ASPN: Payor Number Assigned. |
Mar 30 2012 | STOL: Pat Hldr no Longer Claims Small Ent Stat |
Jun 11 2012 | REM: Maintenance Fee Reminder Mailed. |
Oct 28 2012 | EXP: Patent Expired for Failure to Pay Maintenance Fees. |
Date | Maintenance Schedule |
Oct 28 2011 | 4 years fee payment window open |
Apr 28 2012 | 6 months grace period start (w surcharge) |
Oct 28 2012 | patent expiry (for year 4) |
Oct 28 2014 | 2 years to revive unintentionally abandoned end. (for year 4) |
Oct 28 2015 | 8 years fee payment window open |
Apr 28 2016 | 6 months grace period start (w surcharge) |
Oct 28 2016 | patent expiry (for year 8) |
Oct 28 2018 | 2 years to revive unintentionally abandoned end. (for year 8) |
Oct 28 2019 | 12 years fee payment window open |
Apr 28 2020 | 6 months grace period start (w surcharge) |
Oct 28 2020 | patent expiry (for year 12) |
Oct 28 2022 | 2 years to revive unintentionally abandoned end. (for year 12) |